The present invention is directed to a method for spreading plaster, cement, spackle, or the like, upon wallboard. In the finishing operations of wallboard, tape is usually applied between adjacent blocks of wallboard. Thereafter, plaster is spread over the tape and over adjacent portions of the adjoining wallboard blocks, to thereby fuse together the previously separate blocks of wallboard. Thereafter, in the usual fashion, plaster or the like is applied over the entire wallboard surface area to provide a finished product. The conventional tool for the application of the plaster over the tape adjoining adjacent wallboard portions has been a simple straight knife made of metal. In using this conventional knife in the application and spreading of the plaster, it has taken usually three or four separate and distinct spreading steps in order to correctly and smoothly place the plaster over the tape and adjoining wallboard portions. The multiple-step operation has been necessitated by the fact that the knife in current use must first be used to apply a large amount of the plaster on the wallboard portions, thereafter spreading it in an uneven fashion and, after that, smoothing it out which, by itself, takes usually two or more separate operations. Thus, the actual spreading of the plaster or the like over the tape, adjacent wallboard portions, and the rest of the wallboard portions, has been tedious, time consuming and a multiple-step operation.
The very same knife that has been used to apply the plaster or the like to the tape and adjoining wall portions has also been used to apply spackle to fill in cracks in a wall before the painting of the surfaces. This also is a time consuming and multi-step operation, in the same manner as the above-described application of plaster to wallboard. In the application of the spackle to a crack, what is most important is to fill the crack with the spackle, and to thereafter insure that the wall portions adjacent on either side of the crack are made smooth. Using the conventional knife, this has been, as described above, a difficult task, since the application of the spackle is not done consistently and evenly over the crack and adjoining wall portions thereto.